Fix DAP 'disconnect' implementation

gdb's implementation of the DAP 'disconnect' request was incorrect in
a few ways.

First, the 'terminateDebuggee' field is optional, and has a special
meaning when not supplied: it should do whatever the default is.

Second, if the inferior was attached, it should detach rather than
terminate by default.

Finally, if the inferior was not started at all, it seems reasonable
for this request to simply succeed silently -- currently it returns
"success: false" with the reason being that the inferior isn't
running.

Approved-By: Andrew Burgess <aburgess@redhat.com>

1 files changed, 19 insertions, 3 deletions

diff --git a/gdb/python/lib/gdb/dap/server.py b/gdb/python/lib/gdb/dap/server.py
index bc56a72..64ad247 100644
--- a/gdb/python/lib/gdb/dap/server.py
+++ b/gdb/python/lib/gdb/dap/server.py
@@ -19,6 +19,7 @@ import inspect
 import json
 import threading
 from contextlib import contextmanager
+from typing import Optional
 
 import gdb
 
@@ -618,11 +619,26 @@ def terminate(**args):
     exec_and_log("kill")
 
 
+@in_gdb_thread
+def _disconnect_or_kill(terminate: Optional[bool]):
+    inf = gdb.selected_inferior()
+    if inf.connection is None:
+        # Nothing to do here.
+        return
+    if terminate is None:
+        # The default depends on whether the inferior was attached or
+        # launched.
+        terminate = not inf.was_attached
+    if terminate:
+        exec_and_log("kill")
+    elif inf.was_attached:
+        exec_and_log("detach")
+
+
 @request("disconnect", on_dap_thread=True, expect_stopped=False)
 @capability("supportTerminateDebuggee")
-def disconnect(*, terminateDebuggee: bool = False, **args):
-    if terminateDebuggee:
-        send_gdb_with_response(lambda: exec_and_log("kill"))
+def disconnect(*, terminateDebuggee: Optional[bool] = None, **args):
+    send_gdb_with_response(lambda: _disconnect_or_kill(terminateDebuggee))
     _server.shutdown()